Instrument-transformer.



M. n. DOBROWOLSKY.

INSTRUMENT TRANSFORMER. APPLICATION FILED SEPT. 4, 1912.

' 1,098,6 4, Patented June 2, 1914.

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Inventorf Witnesses Tl'lichaelDolivoD browolskY. %o I WM Y y is aqttczrnex UNITED STATES TENT OFFICE.

ssIoHAEL Domvo DOBBOWOLSKY, or wrm nnsnonr, eEaMANr, ASSIGNOB no GENERAL ELECTRIC COMP A NY,.A CORPORATION 01''- NEW YORK.

iNsTEUMEN'r-TRANSEORMER.

Specification or Letters Patent. Application filed September 4,1812; .SeriaI No..718,538.

Patented J um; 2, 1914.

To all chem {i may concern Be ,it known that 1, MICHAEL DoLIvo Doe'nowonsin', a citizen of the Swiss Rethose other publicfresiding at Wilmersdorf, Germany, have invehted'certain new and useful Improvements in Instrument-Transformers, of

whichthe following is a speci-fication. Y

My invention-relates to instrument" trans-- formers and the ob'ect of my invention is to protect such trans ormers againstjflux 'produced by adjacent-conductors and of which no certain account can betaken in the design or calibration of the 'transformer's'or the instruments supplied thereby, T

Current or' series transformers have for a -l0Ilg' time been used with both single and polyphase'circuits forprov'idinga comparatively -small' current. for measuring and other purposes; the relations of the values ,of the current Gllpplied land the working current should be fixed. The current suppliedby each secondary is of course proportional to the total flux in its iron core and this flu'x maybe appreciably determined not only by the current in the conductor which is surrounded bythat core but. also the current 'in other conductors moreor less remote according to the current'strength in conductors. Thus where the measurement is intended to be made directly from the current in one conductor only, the

' currents in otherfconductors of the same 'fluencing to any appreciable extent adjacent the points where the transformeror transformers are placed. This however,

is usually impossible or undesira le on account of lack of space and the phenomenon of self induction;

My invention prevents the occurrence of any undesired influence by providing each conductor with a magnetic path, that is, a path of a paramagnetic material. completely closed or substantially so, surrounding the same. These magnetic frames surrounding the various conductors are arranged side by side in substantially the sameplane and may be combined into one structure.

Figure 1 shows my invention applied to taken into account during rbration of the devices to be supplied in any .any other conductor 2 two adj acent conductors; Fig 2eshows a modification of the construction of Fig. 1. Fig. 3 shows my invention applied to a number of single-phase feeders, each having-two conductors,'or to a single feeder having a greater number of conductors. Figs. 4 and 5 show my invention applied to a plurality of-'conductors, which may be 'members of a polyplias'e feeder.

In 'Fig. l'the conductors 1 and 2 are any twoadjacent oonductors. They ma be regarded as members of a single fee or supplying some distant point 2. About each of these conductors I have placed a magnetic 'path which, in this case, 'is completely closed; eachof these'paths, all being the same plane and all working below saturation; effectively prevents flux'from its conductor from entering another path. These paths I have here combined into a single magnetic frame 4; the secondary winding 5 .which supplies the instruments has beencated on the comm'on leg 6., As will be understood, the -fl'ux produced by both of the.

mains under these conditions will influence the instrument and the ,instrument will therefore, be calibrated or designed with this in mind. This construction is particularly adapted to the cdndition'that the .'.two conductors are members of the same feeder. .However, there can be no stray and uncalculable flux from either conductor influenccase. were the iron path about one of the mains omitted. Thelo'cation of the selondwinding about p rt of the iron laths which convey fluilinducedby both inal'ns is obviously n mnecessary feature; the'flocatibnof the. secondary on the core must be the design or calicase." Inthe modification of the construction shown in Fig. 1,'which I have illustrated in Fig. 2, an ordinary instrument transformer 4 is located about the conductor 1'. About which itis feared may influence the transformer 4' ijs located the frame 4" providing a magnetic path for the flux from the conductor 2. This frame 4 is located in substantially the same plane as the core. l and therefore shields the core 4 from; flux from the conductor 2.. The secondary 5' may be locatedwherever desired on the core 4,

mg the secondary winding 5,- as would be the \Vhereyer it is desired to measure the combined energy flowing through a plurality of single phztse feeders, asingle path may be disposed about all similar conductors of the various feeders, as is shown in Fig. 3.

'Here again all the paths are combined into a single frame. In this figure, the mains .1

and 2 are members of one of the feeders,

the mains 1 and'2. and l? and'2 bein I 7 D members of two other feeders respectively. The secondarywinding has again been placed about theficommon leg of the core. In this instance-I have shown the secondary winding 7 as divided into two parts, each part being located between two feeders. In this case also, itwill be, apparent that there can be no unacwunted for flux through the iron core and the secondary winding from any of the members of these feeders, proriding of course that.-'-:'the feeders are not bent'back upon t hemselv'e's in-the neighborhood of the core- This would be an-unusual condition. and might be accounted forrby a the mains 10, 11 and Copies of this patent may be obtained for designed to accommodate as manysecondary windings-as there are mains; Fig. 5 produces the saine results while using one less .wlndlng than-there are mains. The meter connections to the secondary windings are well understood."

- What I claim as new and by Letters Patent of the United States, is 1'. The combination with a plurality of conductors, ofa series transformr'conneeted to one of said conductors, and a substantially closed path of paramagnetic material surrounding each of the remaining conductors and lying in substantially the same plane as the core of the transformer.

2. The combination with a plurality of conductors, of a series transforming, device having a substantially closed magnetic path surrounding each of said conductors and a secondary winding surrounding portions of said-paths carrying flux induced therein by a plurality of said conductors.

3. The combination with" a plurality of =-conductors, of a series transformer having a substantially closed magnetic path surrounding each of said conductors, all the paths lying in substantially the same plane, and a secondary winding surrounding portions of said paths carrying flux induced therein by a plurality ofsaid conductors.

at. The combination with a plurality of '40' desire to secure conductors, of a series transformer comprising' a magnetic frame providing a substantially closed path surrounding each conductor and a secondary winding thereon.

In witness whereof, I have hereunto set my hand this 7th day of August, 1912.

MI QHAEL DOLIVO DOBROWOLSKY.

Witnesses:

HEX RY Hasrnn, ARTHUR Sonnosonn.

five cents each, by addressing the Commissioner of Patents- Washington, D. O. 

